Significant research and development effort is currently being applied to various types of extremely dense electronic, magnetic, and optical memories, and various hybrid-technology memories. While the sizes of storage media regions representing stored bits and the speeds of memory access of traditional, magnetic disk memories and electronic memories have steadily decreased during the last 40 years, newer types of extremely dense memories may soon overtake traditional memories in cost efficiency, durability, stored information stability, and other desirable characteristics. Many of the newer types of memories are based on semiconducting organic polymer films and other new materials. Relatively inexpensive, extremely dense, fuse-type memories have been successfully developed from one class of organic semiconducting polymers. In these memory devices, a large current may be used to write the memory, and a lower current may then be used to read the memory. Although fuse-type organic-polymer-film-based memories may be useful and cost effective on a number of applications, including digital-camera memories, researchers and developers of high-density memories continue to recognize the need for new, stable, extremely dense, rewritable memory devices.